Numerical computation of three-dimensional blunt body flow fields with an impinging shock

A time-marching finite-difference method was used to solve the compressible Navier-Stokes equations for the three-dimensional wing-leading-edge shock impingement problem. The bow shock was treated as a discontinuity across which the exact shock jump conditions were applied. All interior shock layer detail such as shear layers, shock waves, jets, and the wall boundary layer were automatically captured in the solution. The impinging shock was introduced by discontinuously changing the freestream conditions across the intersection line at the bow shock. A special storage-saving procedure for sweeping through the finite-difference mesh was developed which reduces the required amount of computer storage by at least a factor of two without sacrificing the execution time. Numerical results are presented for infinite cylinder blunt body cases as well as the three-dimensional shock impingement case. The numerical results are compared with existing experimental and theoretical results

Investigation on the influence of nematophagous fungi as feed additive on nematode infection risk of sheep and goats on pasture

Gastrointestinal nematodes in small ruminants cause high economic losses. Thus on most farms anthelmintic treatment is required. In response to increasing problems with anthelmintic resistance, biological control, for example the use of nematophagous fungi, has received significant attention. The aim of this study was to investigate the effect of Duddingtonia flagrans orally applied to small ruminants on natural infection with gastrointestinal nematodes in a field study in Northern Germany. 20 goats and 20 sheep were fed daily for 3 months with 5x105 spores of D. flagrans per kg bodyweight. Differences in body weight, faecal egg count and larval development in faeces and on pasture in comparison with same-sized control groups were analysed. After 3 months the control goats showed significantly higher mean faecal egg count than the fungus-fed group. No significant difference was found between the two sheep groups. The maximum in larval reduction in faeces was 81.3 % in the sheep groups and 67.9 % in the goat groups (not significant). At the end of the study the body weight gain in the fungus-treated groups was 1.7 kg higher in goats and 0.7 kg higher in sheep than in the control groups (not significant). Regarding the first-year-grazing goats only, the bodyweights revealed significant differences (p<0.05). No statistically significant differences were observed in pasture larval counts. In the study presented here, no clear effect of fungus could be observed. A modified feeding regimen, perhaps with permanent release boluses or feed blocks, may improve the efficacy. Furthermore, it seems that climatic conditions during the study period could have influenced the results and displayed how sensitive the fungus application may be on such parameters

Conclusions

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Predictions for the First Parker Solar Probe Encounter

We examine Alfv\'en Wave Solar atmosphere Model (AWSoM) predictions of the first Parker Solar Probe (PSP) encounter. We focus on the 12-day closest approach centered on the 1st perihelion. AWSoM (van der Holst et al., 2014) allows us to interpret the PSP data in the context of coronal heating via Alfv\'en wave turbulence. The coronal heating and acceleration is addressed via outward-propagating low-frequency Alfv\'en waves that are partially reflected by Alfv\'en speed gradients. The nonlinear interaction of these counter-propagating waves results in a turbulent energy cascade. To apportion the wave dissipation to the electron and anisotropic proton temperatures, we employ the results of the theories of linear wave damping and nonlinear stochastic heating as described by Chandran et al. (2011). We find that during the first encounter, PSP was in close proximity to the heliospheric current sheet (HCS) and in the slow wind. PSP crossed the HCS two times, namely at 2018/11/03 UT 01:02 and 2018/11/08 UT 19:09 with perihelion occuring on the south of side of the HCS. We predict the plasma state along the PSP trajectory, which shows a dominant proton parallel temperature causing the plasma to be firehose unstable.Comment: 16 pages, 5 figures; accepted for publication in the Astrophysical Journal Letter

Arbeitsmarktbindung Nichterwerbstätiger: zur Stillen Reserve in Europa

In addition to employed and unemployed persons, other groups of the society, namely parts of the so-called non-economically active persons, also often enter gainful employment, although they are generally not taken into account in the theoretical and empirical determinations of a country's labour force. One reason for this is the difficulty to identify empirically this "hidden labour force". Based on the European Household Panel (ECHP) in the years 1994, 1995 and 1996, this study takes a closer look at the hidden labour force by comparing 12 member states of the European Union in both longitudinal and cross-sectional contexts. A method for identifying non-economically active persons who maintain strong links to the labor market - the group of the 'ATTACHED' - is developed and used to analyze both the extent and behavior of the statistically not registered labour supply. The usefulness of such an approach is confirmed by our results, which indicate the relatively high tendency of persons in this group of the ATTACHED to enter into gainful employment. A longitudinal study of the transition into employment in two different years - based on the averages for all 12 countries together, clearly indicates that unemployed persons did not even account for half of the persons who entered into gainful employment. Comparisons of the various countries cast doubt on simple macroeconomic explanations for the behavior of persons in the group of the ATTACHED. A larger percentage than the average of this group is, for example, associated with a higher than average level of unemployment in some, but not all of the EU countries considered. Neben Erwerbslosen nehmen auch sonstige Nichterwerbstätige häufig eine Beschäftigung auf. Diese Personen werden jedoch gewöhnlich nicht bei der empirischen Bestimmung des Arbeitsangebotes erfasst. Ein Grund liegt in der Schwierigkeit ihrer Erhebung, da sie üblicherweise in keinen Registern der Arbeitsverwaltung gezählt werden. Auf Basis des Europäischen Haushaltspanels (ECHP) für die Jahre 1994, 1995 und 1996 geht die vorliegende Untersuchung diesem Phänomen im Vergleich von 12 Staaten der Europäischen Union in Quer- und Längsschnittuntersuchungen nach. Es wird ein Konzept zur Erhebung einer Stillen Reserve im Sinne von Nichterwerbspersonen mit einer besonders hohen Arbeitsmarktbindung entwickelt (die sogenannte Gruppe der ATTACHED). Auf Basis dieses Konzept werden Umfang und Verhalten dieser Gruppe untersucht. Die Ergebnisse bestätigen den gewählten Ansatz und zeigen die vergleichsweise hohe Erwerbsneigung dieser Gruppe (ATTACHED) am Arbeitsmarkt auf. Unter Berücksichtigung weiterer Nichterwerbstätiger, die eine Erwerbsarbeit aufnehmen, ohne als erwerbslos erfasst worden zu sein, wird bei Vergleichen der Übergänge in Erwerbstätigkeit zwischen zwei Jahren deutlich, dass im Durchschnitt der EU-12 Staaten Arbeitslose nicht einmal die Hälfte der Personen ausmachen, die von einem Jahr auf das andere in die Erwerbstätigkeit wechseln. Der Vergleich zwischen den einzelnen Ländern stellt zudem einfache makroökonomische Erklärungsmuster zum Verhalten von Personen in der Gruppe der ATTACHED in Frage. Beispielsweise ist ein überdurchschnittlicher Umfang der ATTACHED in einigen aber nicht allen EU-Länder, mit einer überdurchschnittlichen Erwerbslosigkeit verbunden.Hidden Labour Force, Labour Market Attachment, Employment Transition Rates, Labour Market Performance

Protective effect of bacterial lipopolysaccharides in the grapevine- Agrobacterium vitis interaction

Cell-associated lipopolysaccharides (LPS) were extracted by the phenol-chloroform-petroleum ether extraction method (PCP) from a nopaline strain of Agrobacterium vitis, purified by treatment with DNase/RNase, proteinase K and dialysis, characterized by polyacrylamide gel electrophoresis (SDS-PAGE), and bioassayed on grapevine shoot nodal segments. LPS preparation used for the experiments in planta was a mixture of rough-type LPS, obtained from precipitation with water after PCP-extraction, and some smooth- and rough-type LPS from the remaining phenol phase. Infiltration of an aqueous dispersion of the mixture in concentrations of 25-1000 µ g.ml-1 did not cause grapevine tissue necrosis, and callus formed within one month. When the LPS dispersions were infiltrated in the grapevine nodal segments, 24 h before challenge inoculation with A. vitis (5x102 cells per 5 µ l droplet), they prevented tumorgenesis and tissue necrosis; but, when the pathogen was inoculated at a higher concentration (5x105 cells per 5 CII droplet), these LS applications were active in protecting plant tissue from necrosis and did not prevent tumor induction. The potential role of LPS as candidate molecules in the protection of grapevine from A. vitis infection is discussed

Empirical Modelling of Trade and the Environment

Not available

Black Holes and Wormholes in 2+1 Dimensions

A large variety of spacetimes---including the BTZ black holes---can be obtained by identifying points in 2+1 dimensional anti-de Sitter space by means of a discrete group of isometries. We consider all such spacetimes that can be obtained under a restriction to time symmetric initial data and one asymptotic region only. The resulting spacetimes are non-eternal black holes with collapsing wormhole topologies. Our approach is geometrical, and we discuss in detail: The allowed topologies, the shape of the event horizons, topological censorship and trapped curves.Comment: 23 pages, LaTeX, 11 figure

Growth, Trade, and the Environment Nexus in Chile: A Comprehensive Assessment

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TAIR: A transonic airfoil analysis computer code

The operation of the TAIR (Transonic AIRfoil) computer code, which uses a fast, fully implicit algorithm to solve the conservative full-potential equation for transonic flow fields about arbitrary airfoils, is described on two levels of sophistication: simplified operation and detailed operation. The program organization and theory are elaborated to simplify modification of TAIR for new applications. Examples with input and output are given for a wide range of cases, including incompressible, subcritical compressible, and transonic calculations